North Korea said on Thursday that South Korea must stop trying to mediate between Pyongyang and Washington, as it stepped up its pressure on the United States to work out new proposals to salvage deadlocked talks on its nuclear programme.
Kwon Jong Gun, chief of the North Korean Foreign Ministry's US affairs department, said the country would "never go through" South Korea again in dealing with the country.
Kwon also dismissed as false comments by South Korean President Moon Jae-in and other South Korean officials that there were various exchanges and unofficial talks between the two Koreas.
"It's better for the South Korean authorities to mind their own business at home," he said, according to the Associated Press.
The statement came two days before US President Donald Trump visits South Korea for a two-day trip ahead of the G20 Summit in Japan.
There have been no public meetings between the United States and North Korea since the breakdown of the second summit between Trump and North Korean leader Kim Jong Un in Hanoi in February.
The summit's collapse was a blow to South Korea's Moon, who had shuttled between Washington and Pyongyang to help facilitate diplomacy over the North's nuclear ambitions.
Hopes that talks would resume were revived after Trump and Kim recently exchanged personal letters, and Moon said US and North Korean officials were holding "behind-the-scene talks" to try to set up a third summit between the two countries' leaders.
Kwon's statement follows last week's visit to the North by China's President Xi Jinping - the first by a Chinese leader in 14 years.
Some experts have said Xi's trip was an indication that China, the North's main ally and economic partner, wanted to play a bigger role as a mediator in the nuclear issue to increase its leverage with Washington over trade disputes.
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